Orthodontic appliance



FIG. 1 is a perspective view of the orthodontic appliance showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a left side elevational view thereof, the right side being a mirror image;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof. 

The ornamental design for an orthodontic appliance, as shown and described. 